This invention relates to a method for improving certain properties of fibrous forms of cellulose acetate by way of a chemical aftertreatment.
Various fibrous forms of cellulose acetate are in widespread current use in diverse products. Woven or knitted fabrics comprised of fine denier continuous filament cellulose acetate find extensive application for lingerie, sleepwear, interlinings and blouses. Heavier deniers of continuous filament cellulose acetate are utilized in crimped and uncrimped form in drapery, curtian and upholstery fabrics. Spun yarns comprised entirely or in part of staple length cellulose acetate fiber are utilized in various apparel fabrics where a high loft or soft texture is sought. In non-fabric applications, cellulose acetate fibers find extensive use in the production of cigarette fibers and battings used for cushioning or insulative purposes.
Two distinct types of cellulose acetate fiber are recognized, namely secondary acetate and triacetate, both being produced by the acetylation of cellulose with acetic anhydride. Secondary cellulose acetate, which is soluble in acetone, has an average degree of acetylation of between about 1.8 and 2.3 acetyl groups per anhydroglucose unit of the cellulose molecule. Solutions of the secondary acetate in acetone are utilized for the production of fibers by a dry spinning technique wherein the solution is extruded through a spinnerette downwardly through an elongated evaporative chamber.
Cellulose triacetate has an average degree of acetylation between about 2.3 and 2.9, and is generally dry spun into filaments from methylene chloride/alcohol solutions. It is a hydrophobic fiber, having a normal moisture content of about 2%. In comparison to secondary acetate fibers, triacetate fibers are less sensitive to hot water and provider greater wrinkle resistance in fabrics. Despite the several property improvements produced by the higher degree of acetylation of the triacetate, further improvements in the characteristics of acetate fibers have long been sought. In fabrics, sought improvements have been in the areas of wrinkle resistance, permanent press capability, increased moisture regain, freedom from static build-up, and soil release.
It is accordingly an object of the present invention to provide a treatment of cellulose acetate fiber which will improve the characteristics of fabrics comprised of said fiber.
It is another object of this invention to treat fabrics comprised of cellulose acetate fiber to improve the characteristics of said fabrics.
It is a further object to the present invention to provide a treatment of the aforesaid nature which is economical and easily controllable.
These objects and other objects and advantages of the invention will be apparent from the following description.